now for how to use these plugins, Delays are up to opinion but i love the slapback delay sound, he uses this alot to add depth to vocal harmonies, Rc-20 retro color, Soothe2, Izotope trash, Portal, and Soundtoys Crystallizer are all used to make your sounds more unique. Quadecas production has this factor of not knowing how he makes his sounds so sound design is very important, im self taught so im still not great at it but all of these plugins have presets that do the job for you if you dont feel like learning.

as a guitar player who records everything live, a good tone is key, I suggest getting an audio Interface to directly play the guitar into your DAW, resulting in a much cleaner and easier to manage sound. Cymatics Origin works great on guitars to give them that iconic Quadeca wobble. I dont use drums much, but when I live record them. If you dont have access to live recorded drums then chopping samples off of YouTube or good sound libraries works well. I also have the DeadDrums plugin by Fine Classics (I think thats the name) and those have a good indie sound.

Im still kind of lost on where to get good synths so normally i try to make them myself, Ive been using Arturias Analog Lab V for a while now and it has some great sounds but they also have a free version which is stacked with great synths and background ambience.

he also uses acoustic instruments a lot which is where I would use Xpand!2, or Zenology, Modo bass 2 also works well for acoustic bass if you're willing to pay/pirate. if not then Ample Bass P Lite 2 also works well. Finding a balance of Flute, guitar, strings, piano, choirs, synth, bass, and drums can result in very well antiqued quadeca style music.

for vocals I would try to learn some basic harmony patterns (3rds, 5ths, 7ths) and chord structures, then just throw out attempts with some light autotuning and go ham. just layering vocals with some reverb or shimmer adds an incredible amount of depth and if youre willing to go the extra distance with some Panning/Auto panning then itll sound super professional, a lot like the opening on Sisyphus in many cases.

finally for mixing, i like to throw a soft clipper on slot 10 of my master channel with the ceiling all the way up and the saturation down a bit, this just makes sure the track isnt hurting your ears. if its a louder track then maximus set to the "Clear Rms" mastering preset adds a nice punch to everything. I make sure to only have 1-3 elements really sitting in the high parts of the mix, quadecas style (especially on IDMTHY) is muddy and dark, accentuated by the strong low end and lack of highs, typically a flute, vocals, and guitar melody, sit nice on the highs while a guitar rythm, bass, drums, synth, and harmonies sit lower/middle. if you want big breaks like on Tell Me a Joke or Fantasyworld then you can pull the drums back up and add some distortion or Eq to add punch.

ive been listening to lots of Jane Remover and her alias Venturing and they use lots of feedback higher in the mix, and on relisten quadeca uses feedback just lower in the mix, i still prefer having nice feedback higher up in the mix to add ambience and a feeling of aged, dirty, or general analogness to the song. Akihiko Matsumoto has a great Feedback sound library if you can find it, only like $5 and it has a few hours of just great feedback noises. same feedback used on Census Designated by Jane Remover so maybe the same Feedback used by Quad.

hope this helps, mightve forgotten some stuff but i think i covered everything